Circuit breaker



J. ROG

CIRCUIT BREAKER Jan. 19, 1937.

` Filed April- 8v, 1935 LIC nvdr

INVENTOR. JHN P06.

ATTORNEY/ f f M N, mmmmmwwmm@ f wg? n t 2:92:11 A EEEEE u. w 1/1.////////YH 4 Patented Jan. 19, 1937 UNITED STATES PATENT OFFICE l Claim.

This invention relates to that class of electrical devices whichinterrupt the iiow of current when too great a load is interposed in thecircuit, known as fuses, which at a certain value of current and timerupture the circuit.

Fuses as commonly made require replacement after becoming blown orhaving served their purpose of causing cessation of current, and suchreplacement is usually inconvenient to accomplish under any conditionand'particularly so in the dark; moreover, 4a substitute fuse is notalways at hand.

It is therefore an object of the present in.- vention to provide acircuit breaker to be inserted in the circuit, that is instantlyresponsive to an excess of heat, caused by the current passingtherethrough, and break the circuit, cutting ofi the current.

A further feature is in the provision of means within the circuitbreaker Ifor reinstatingY the flow of current automatically after amomentary overload, entirely Without manual effort, this beingself-resetting.

Another purpose is to produce an automatic resetting circuit breaker ofneat appearance, inexpensive construction and capable of long extendedservice. v These advantageous objects are attained by the novelconstruction, combination and arrangement of few and simple partshereinafter described and illustrated in the accompanying drawing;forming a material part of this disclosure, and in which;-

Figure l is a side elevational view ci an embodiment of the invention asassembled ready for use. f

Figure 2 is a partial side elevational, partial longitudinal sectionalview of the same drawn to an enlarged scale.

Figure 3 is a longitudinal sectional View taken on line 3-3 of Figure 2.

Figure 4 isa transverse sectional view taken on line 4 4 of Figure 3,showing the circuit closed.

Figure 5 is a similar sectional View taken in the same plane, butshowing the circuit breaker in an open position.

As shown in the drawing the device consists of a tubular casing I oiinsulating material, as indurated ber, into the socket connecting end ofwhich is set a sleeve li, having at its outer extremity a disc I2 ofdielectric material provided at its outer face with a hub-like extensionI3. The extending portion of the sleeve H has formed on it the usualstandard screw thread (Cl. 20o-113) and is enveloped in a screw shell i4of conducting material, provided with an inreaching annular ilange l bywhich the'disc i2 is tightly clamped against the end of the sleeve ll.

The upper edge of the shellmakes contact with the adjacent edge of thecasing l0 and constitutes a plug adapted to engage a standard socket.

Fixed in an internal longitudinal groove il of the casing IB is aconductor strip i8 having its lower end i9 in electrical engagement withthe shell i4 and at its opposite, outer end is a contact block 20, suchas carbon, held rigidly to it by a bolt 2i, this block extendingradially into the hollow casing l0 near its outer end.

Fixed on the outer side of the disc hub i3 is a button shaped conductivecontact 22 having a stem 23 passing axially through the disc l2, and

formed on the stem is a thin, coiled bi-metallic` helix constituting athermostatic coil 24, extendlng centrally into the casing I0 towards itsouter end.

The upper end of the helix is inbent as at 25, and xed to a collar 26firmly secured on an axial conductor rod 21 freely rotatable in thecasing and extending from a point near the disc l2 to the outer end ofthe casing where it passes through a central opening in a disc 28 ofdielectric material, such for instance, as mica.

The disc 28 acts as a cover for the casing I0 and is held in positiontherein by a spring retaining ring 29 set in an internal annular groovein the uppermost part of the casing.

Surrounding the rod 21 is a guard tube 30 and adjustably clamped to therod, at a point beyond the tube, is an arm 3l on the end of which ismounted a carbon contact 3l' adapted to normally rest against the sideface of the contact block 20.

, In operation the circuit breaker is entered into any ordinary socket,one pole of the current being conducted by the shell I4 to the block 20by the conductor I8, while the other pole is conducted by contact 22 tothe helix 24, rod 21, arm 3|, and carbon contact 3i', which is normallyengaged with the block 20, thus forming a complete circuit.

Upon imposing an overload on the circuit heat is instantly generated,causing the coiled helix to expand and move the arm 3l from the block,see Figure 4, into a remote position, as seen in Figure 5, thus breakingthe circuit.

The helix 24 quickly cools, re-establishing the circuit by closing thearm upon the block and conveying current therethrough.

Due to the plurality of coils in the helix it is the circuit, andobviously no labor or even attention is required.

Although the foregoing is descriptive of the preferred embodiment of theinvention, it will be apparent that minor changes may be made in itsconstruction. without departing from the scope of the claim heretoappended.

Having thus described the invention what is claimed as new and desiredto secure by Letters Patent, isz- A circuit breaker plug comprising adielectric tubular casing having a sleeve tight fitted in one end, adielectric disc at the outer end of said sleeve, a screw threadedconductive shell enclosing the extending portion of said sleeve andinstantly responsive both in making and breakingclamping said discthereto, a strip conductor Fixed in said casing in electrical contactwith said shell, a carbon block carried by said Conductor to extendradially into said casing, a Contact fixed centrally on said disc, athermostatic helix in electrical engagement with said Contact, saidhelix extending axially into said casing, a .rod :xed on the extremityof said helix to pass axially therethrough, a guard tube on said rod, acontact arm supported and actuated by the outer portion of said rod tonormall;r rest against said block and movable therefrom upon theimposition olf an overload in the circuit, anda transparent cover forsaid casing.

JOHN

